RpLidarSerialDevice

Namespace: RpLidar.NET

Low-level serial device implementation of ILidarService with full protocol control.

Table of Contents

1. Definition
2. Constructors
   1. RpLidarSerialDevice(ILidarSettings settings)
3. Events
   1. LidarPointScanEvent
   2. LidarPointGroupScanEvent
4. Methods — Lifecycle
   1. Connect()
   2. Disconnect()
   3. Start()
   4. Stop()
   5. Dispose()
5. Methods — Motor Control
   1. StartMotor()
   2. StopMotor()
6. Methods — Scanning
   1. StartScan()
   2. ForceScan()
   3. ForceScanExpress()
   4. StopScan()
7. Methods — Protocol
   1. SendRequest(Command command)
   2. SendCommand(byte command, byte[] data = null)
   3. Read(int len, int timeout)
8. Remarks
9. See Also

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Definition

public class RpLidarSerialDevice : ILidarService

RpLidarSerialDevice implements the complete SLAMTEC serial protocol v2.1. It gives you explicit control over connection, disconnection, scan mode, motor speed, and request/response cycles.

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Constructors

RpLidarSerialDevice(ILidarSettings settings)

Creates a new device instance. Does not connect to the port until Connect() is called.

Parameter	Type	Description
settings	ILidarSettings	Configuration: port, baud rate, scan mode, PWM, etc.

var settings = new LidarSettings
{
    Port     = "/dev/ttyUSB0",
    ScanMode = ScanMode.Standard
};
var device = new RpLidarSerialDevice(settings);

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Events

LidarPointScanEvent

public event LidarPointScanEvenHandler LidarPointScanEvent;

Fired every settings.ElapsedMilliseconds (default 400 ms) with raw points from the current scan window.

LidarPointGroupScanEvent

public event LidarPointGroupScanEvenHandler LidarPointGroupScanEvent;

Fired alongside LidarPointScanEvent with the same points wrapped in a LidarPointGroup (angle-indexed at 0.1° resolution).

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Methods — Lifecycle

Connect()

public void Connect()

Opens the serial port and initialises the device. Call before any other method.

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Disconnect()

public void Disconnect()

Closes the serial port. Call after Stop().

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Start()

public void Start()

Convenience method that:

1. Calls Connect() (if not already connected)
2. Sends StopScan
3. Detects the scan mode from settings.ScanMode
4. Starts the appropriate scan command
5. Launches the background scan thread

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Stop()

public void Stop()

Sends StopScan and terminates the background scan thread.

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Dispose()

public void Dispose()

Stops the scan, stops the motor, disconnects, and releases all resources.

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Methods — Motor Control

StartMotor()

public void StartMotor()

Sends the motor-start PWM command using settings.Pwm (default 660).

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StopMotor()

public void StopMotor()

Sends the motor-stop command (PWM = 0). The sensor will stop rotating.

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Methods — Scanning

StartScan()

public void StartScan()

Sends the standard Scan command (0x20). Compatible with all supported models.

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ForceScan()

public void ForceScan()

Sends the ForceScan command (0x21). Bypasses the motor-sync check — use when motor synchronisation is not needed.

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ForceScanExpress()

public void ForceScanExpress()

Sends the ExpressScan command using settings.ScanMode. Issues the Boost (working_mode=3) or Sensitivity (working_mode=4) sub-mode as appropriate. Only supported on A2M8 and A3M1.

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StopScan()

public void StopScan()

Sends the Stop command (0x25) to halt the current scan without stopping the motor.

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Methods — Protocol

SendRequest(Command command)

public IDataResponse SendRequest(Command command)

Sends a single-response command and returns the parsed response.

Parameter	Type	Description
command	Command	The protocol command to send

Returns IDataResponse — cast to InfoDataResponse or RpHealthResponse as appropriate.

var info = device.SendRequest(Command.GetInfo) as InfoDataResponse;
Console.WriteLine(info?.ModelId);

var health = device.SendRequest(Command.GetHealth) as RpHealthResponse;
Console.WriteLine(health?.Status); // 0=OK, 1=Warning, 2=Error

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SendCommand(byte command, byte[] data = null)

public IDataResponse SendCommand(byte command, byte[] data = null)

Low-level raw command send. Prefer SendRequest with the Command enum for standard commands.

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Read(int len, int timeout)

public byte[] Read(int len, int timeout)

Reads exactly len bytes from the serial port, waiting up to timeout milliseconds.

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Remarks

• Call Connect() before any other method (or call Start() which calls it internally).
• All events fire on a background thread. Do not update UI controls directly from event handlers.
• To change scan mode after construction, create a new RpLidarSerialDevice with updated settings.

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See Also

• RPLidar — simpler high-level wrapper
• ILidarSettings / LidarSettings — full settings reference
• Command — all available protocol commands